Wernicke's Encephalopathy Classical Features

Wernicke's encephalopathy (WE) is an acute neurological condition typically caused by thiamine (vitamin B1) deficiency.

Identifying Classical Signs of WE

The classic triad of symptoms associated with Wernicke's encephalopathy includes:

• Ophthalmoplegia (or Horizontal nystagmus): This involves paralysis or abnormal movements of the eye muscles.
• Ataxia: Lack of voluntary coordination of muscle movements.
• Encephalopathy (Confusional state): This refers to altered mental status, ranging from mild confusion to stupor or coma.

Analyzing the 'Except' Feature

The question asks to identify the option that is NOT a classical feature of Wernicke's encephalopathy. Let's examine the options:

• Horizontal nystagmus: A recognized sign of ocular muscle dysfunction in WE.
• Confusional state: A key component of the encephalopathy in WE.
• Opthalmoplegia: Another sign of ocular muscle dysfunction in WE.
• Extension plantar response: This sign, also known as the Babinski sign, indicates dysfunction of the corticospinal tract (upper motor neuron). It is not a characteristic feature of Wernicke's encephalopathy, which primarily involves the diencephalon and brainstem due to thiamine deficiency.

Therefore, the extension plantar response is the feature that is excluded.

The classical features of Wernicke's encephalopathy are ophthalmoplegia (or nystagmus), ataxia, and confusion. An extension plantar response is not among these classical signs.